Review on Precision Jewelry Plastic Assembling 0 5 3 0Mm by Alfredo Testerman

The holder is inaccurate but that is to be expected. What was not to be expected is that the bits have no sharp corners and are not hardened. You need to grind down your points and then heat treat them. They are still unusable after heat treatment as they are mild or medium steel which means the bits will either snap or bend in a light breeze. Purchase a set of carbide bits for these sizes. It's worth the extra $4